Driving finger for surfacing machines



Oct( 18, 1932. H. c, sT. DENNIS DRIVING FINGER FOR SURFACING MACHINES Filed May 50. 1930 o LW@ 5;

BY Mfwm ATTORNEYS.

Patented` Oct. 18, 1932 UNITED STATES HAROLD C. ST. DENNIS,y OF SYRACUSE, NEW 'YORK DRIVING FINGER FOR SURFACING MACHINES app'iieation sie@ may so,

This invention relates to driving fingers for surfacinov machines, and particularly .to the driving fingers of machines used for sur-v facing lenses such as used by Opticians.

It has been the conventional practice `to use steel bars as driving fingers on surfacing machines for lenses. In operation, these machines are extremely noisy due tothe elattering of the steel driving fingers' against i the steel arms of the block holders.1 This is particularly undesirable where 'a grinding machine, or av number of them, are usedin a. room close to a waitingrroom or office, as is. very often the case. Various lefforts have been made to quietl these machines, such as wrapping the driving fingers with tape, buty such eiorts have been unsuccessful; the tap wearing out in a few days.

In a machine using steel driving fingers,

"i,- the wear of these lingers is yextremely rapid.;

'ifi it is necessary where the surfacing machine is in constant use, to replaceithe driving fingers after a comparatively few weeks. Since only a portion of the upper part of a driving finger is worn out, unnecessary eX- pense is entailed in replacing the entire member. Removal of worn driving `fingers and their replacement with new ones consumes some little time which oft-en can not be well spared in a busy shop.

l/Vhen the driving fingers of a lens surfacing machine become badlyworn, theaccuracy of the machine for lens grinding is often seriously impaired. l

An obj ect of this invention is to provide an improved driving finger for `surfacing ma,-` chines, and particularly lens surfacing machines, which will be quiet in operation. A further object is to provide a driving finger having a body portion of suflicient rigidity 5"" for driving purposes, and a bearing face,

1930. seriai No. 457,648.

mounted on the lbody portion, of softer material better adaptedy for bea-ring contact than the material of the body portion.

A further object of the invention is to provide a driving finger having a bearing face which may be replaced when worn without requiring replacement of the entire driving finger. A further obj ect is to provide a driving finger having a Wearingsurface of such material that it is impossible Lfor small hard particles to be displaced therefrom withv the dangeryof causing scratching of the lens.

A further object of the invention is to provide a driving finger having a replaceable bearing face which maybe removed or inserted without dismantlingthe machine, or removing the driving fingers from theirope'rative position.y

Other objects and advantages will be pointedout and will become apparent as the description proceeds. f

The invention consists in the novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is had tothe'accompanying drawing, in which like characters designate corresponding parts in allr theY views.

Figure lv is a perspective view of a lens surfacing machine to ywhichy my improved driving fingers are applied. i

Figure 2 is a front elevation of my iniproved driving-finger.

Figure 3 is a side elevation of thedriving linger illustrated vin FigureQ. f

Figure 4 is a front elevation of a driving finger showing my invention applied thereto in ka modified form.

Figure 5 is a side elevation of the driving finger illustrated in Figure 4.

Figure 6 is an elevation showing a detailed view of themeansfor mounting the driving fingers.

Figure l illustrates an automatic surfacing machine of the conventional type used Lfor F lens grinding.` A torque or cylinder attachment l0 is driven by suitable operating mech anism. A block l1 is mounted on the cylinder attachment and the lens to be surfaced is secured to a lens block holder 12 which holds i arms 13 which extend between driving fingers 14. The driving fingers 14 are secured by suitable means, such as a clamping screw 15, to the cylinder attachment. Thus, the oscilu lating rotary motion of the cylinder attachment 10 will be imparted through-the driving fingers 14, and arms 13, to the lens block holder 12 on which the lens is mounted.

A throw crank 2() and crank pin 21 cooperate with the arms 13 to give the lens Yblock holder 12 the necessary composite sliding action on the block 11. This feature of the drive is well known to those learned with lens surfacing machines, forms no part of the present invention, and a detailed vdescription of it is unnecessary.

When the cylinder attachment 10 os'cillates in a clockwise direction, thearms 13 willV be driven by the left hand driving fingers. When the cylinder attachment oscillates in a counter-clockwise direction, the arms 13 will be driven bythe left hand driving fingers. To allow perfect freedom of motion of the arms 13 between the driving lingers 14 it is necessary that some play be provided. Due to this play there is necessarily a certain amount of clattering between the arms 13 and driving fingers 14.

Referring to Figures 2 and 3, the driving finger 14 is provided with a cut-out portion into which a bearing face 25 is inserted. This bearing face preferably forms a fiush surface with thebody portion of the driving finger as shown in the drawing, though this is not necessary. The bearing surface 25 is secured to the driving finger 14 by any suitable means, and in the form of the invention shown in Figures 2 and 3, by counter-sunk screws 26.

The bearingv surface may be made of any suitable material. Y I prefer to use tough rubber or leather, or composite materials having similar properties. Good results however, can be obtained with other materials such as fiber board.

The modification of the invention shown in Figures 4 and 5 provide means lwhereby the bearing surface may be replaced without removing the driving fingers from operated position. vThe construction of the driving finger is identical with that described in connection with Figures 2 and 3.` The bearing face however, instead of being secured in place by screw means, is held in place by a cap 27 which fits over the end of the driving fin er.

v YrThe cap 27 extends suiliciently far onto the body portion of the driving finger to hold both ends of the bearing face against displacement. A cut-out portion is provided in the cap 27 so that the arms 13 will contact with the bearing face. The cap 27 fits over the top of the driving finger 14, and the end of the c ap will rest against the top of the driving finger to hold the cap in position.

I have found that a bearing surface of rubber, leather, or like material, will greatly outwear a steel bearing surface in a. device of this kind. When the bearing surface 25 eventually becomes worn it may be replaced, in a manner which will be readily understood from the above description, and there is no necessity for buying a complete new driving finger.

While I have illustrated the preferred embodiment of my invention, various changes and modifications may be made in the details of construction without departing from the spirit of the appended claims.

Vhat I claim is 1. A torque attachment driving linger for a lens grinding machine including a body portion with a cut-out section in a face thereof; a replaceable bearing member inserted in said cut-out section to provide a wearing face for the driving linger; and a sleeve formed to fit over a part of the driving finger and bearing member for securing the bearing member to the body portion; said bearing member being constructed of soft material so that the grinding machine will operate with less noise than when operating with an unsurfaced driving finger.

2. A lens grindingV machine including in combination a pair of driving fingers; means securing the driving fingers to a driven member; a lnens block holder; a driven arm connected to the lens block holder and extending between the driving fingers; bearing faces of soft material mounted on the driving fingers in position to contact with the driving arm whereby the driving fingers will operate the driven arm with less noise than the unsurfaced linger; and means, formed to slide over a portion of the driving fingers and removable and replaceable while the driving lingers are in operative position, for holding the bearing faces in position on the driving fingers.

3. As an article of manufacture a driving finger for grinding machines including a body portion having a ycut-out section; a bearing member of soft tough material inserted in the cut-out section to provide a wearing face for the driving finger whereby the grinding machine will operate with less noise than when operated with the unsurfaced driving linger; and retaining means formed to slide over a part of the body portion and of the bearing member for holding a bearing member in place.

4. As an article of manufacture a driving finger for grinding machines including a body portion having a cut-out section; va bearing member of soft tough material inserted in the cut-out section to provide a wearing face for the driving finger whereby the grinding machine will operate with less noise and the Wearing face last longer than When operated With the unsurfaced driving finger; and a sleeve formed to it over the driving finger and provided with a cut-out portion exposing that part of the bearing member which serves as the Wearing face.

In testimony whereof, I have hereunto signed my name, at Syracuse, in the county of Onondaga, and State of New York, this 29th day of May, 1930.

HAROLD C. ST. DENNIS. 

